[electron-update-server] Introduce new version

Summary:
New release after fixes for ENG-4073, diff: D8208.

• now there's a repository in docker hub so added commapp/ to the image
• needed to update the Dockerfile to match the keyserver one

Test Plan: Build docker image and push to docker hub

Reviewers: bartek, varun, jon

Reviewed By: bartek, varun

Subscribers: atul, ashoat, tomek

Differential Revision: https://phab.comm.dev/D8305